Spectrum analyzers such as Radio Frequency (RF) spectrum analyzers analyze radio frequency waves. By analyzing the spectra of electrical signals, a spectrum analyzer can determine frequency, power, distortion, harmonics, bandwidth, and other spectral components of an input signal. These parameters are useful in the characterization of electronic devices, such as wireless transmitters. Spectrum analyzers may also be used in Fast Fourier Transform functions for converting a time domain sequence of numbers or signals to a frequency domain.
They are typically used in laboratory settings to analyze devices that output radio frequencies, such as cell phones. For example, a cell phone manufacturer may test the output or input of a cell phone, Wi-Fi router, a laptop with Wi-Fi to determine the radio frequencies transmitted or received by the device. Such RF spectrum test equipment is made, for example, by companies such as Agilent (formerly of Hewlett Packard), Rohde & Schwarz, Tektronix and Anritsu. They also use to be made by Hewlett Packard.
RF spectrum analyzers may be used in electronic warfare or military applications, for example, to trick a radar by searching for a radar signal and returning an intentionally modified signal back. In this respect, they are also used in a Digital Radio Frequency Memory (DRFM) which is an electronic method for digitally capturing and retransmitting an RF signal, typically used in radar jamming. DRFM digitizes an RF signal with an Analog to Digital (A/D) converter, and possibly a down-converter which converts the frequency to a lower frequency to be converted to digital. The output of the A/D converter is stored in digital memory, and the digital memory is used by a processor to do desired signal processing. It is then passed to a digital to analog converter (D/A) converter and then amplified. It is also possibly up-converted in frequency and retransmitted. A DRFM system is designed to digitize an incoming RF input signal at a frequency and bandwidth necessary to adequately represent the signal, and then reconstruct that RF signal when required. A DRFM may modify the signal prior to retransmitting which can alter the signature of the false target, adjusting its apparent radar cross section, range, velocity, and angle, thereby presenting a significant obstacle for radar sensors.
However, conventional spectrum analyzers are very expensive, large and consume a lot of power. They are large, expensive pieces of equipment intended for laboratory settings, and may be, for example, two and a half feet long and deep and a foot tall, weighing roughly 60 pounds. They may also cost tens of thousands of dollars, for example. They are conventionally more specialized pieces of equipment that give a different view into the RF and microwave spectrum than one can get with an oscilloscope, for example.
Accordingly, there is a desire for an RF spectrum analyzer on a smaller scale and for lower pricing. Consequently, there is a desire to solve these and other related problems.